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Gulfaholic Samba Member
Joined: January 18, 2017 Posts: 14
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Posted: Wed May 24, 2017 4:59 pm Post subject: Burnt distributor on msd ignition |
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I bought a 71 bug that had an msd electronic ignition installed on it. Driving it last weekend I felt it missing and poping. I pulled over and check under the engine lid to find the distributor cap had a hole melted in it and the coil wire burned up. Any thoughts on why this might of happened. I have ordered a new cap, wire and rotor. But before I install it I would like to make sure this issue is not going to happen again. Any info would be appreciated. Thanks.
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[email protected] Samba Member
Joined: May 17, 2003 Posts: 4863 Location: Harmony, PA
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Posted: Wed May 24, 2017 7:09 pm Post subject: Re: Burnt distributor on msd ignition |
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The good thing about a MSD setup is the power of the spark. The bad thing about a MSD setup is the power of the spark. It pretty much throws a spark anywhere. If you had a crack in the cap, the coil wire was slightly loose, or the rotor was worn, the spark will easily jump gaps causing heat. There's a picture in one of the VW forums where someone had their MSD cap loose for some reason, started cranking the engine, only to have the spark run down the side of the rotor to the distributor base. It looked like black carbon lightning bolts on the rotor. |
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ashman40 Samba Member
Joined: February 16, 2007 Posts: 15975 Location: North Florida, USA
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Posted: Wed May 24, 2017 10:03 pm Post subject: Re: Burnt distributor on msd ignition |
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Where is the center post of the distributor cap? Did it melt off?
Just a question on your spark plugs... what make/model and how wide is your spark plug gap? I'm guessing that coil is outputting much more than the typical 15-18,000v from the stock coil? With much more voltage you need to open up the plug gap to 0.035" or maybe more. But if you make it too wide the spark may look for somewhere else to ground.
I'm impressed with the carb!
A Holley 4bbl carb on a 1bbl center mount DP intake... 4-into-1! How do you keep the fuel atomized in the intake without heat riser tubes?
If I do my math correctly, a 450cfm 4bbl Holley carb (smallest of the 4bbl Holley carbs) can flow enough (CFM) to get a 122ci (2000cc) engine up to 15,000rpm! Or a 98ci (1600cc) engine up to 19,000rpm!
That might be a bit too much carb for your engine... but it sure does look cool! _________________ AshMan40
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'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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Bashr52 Samba Member
Joined: July 16, 2006 Posts: 5666 Location: On an island in VA
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Posted: Thu May 25, 2017 4:20 am Post subject: Re: Burnt distributor on msd ignition |
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ashman40 wrote: |
I'm impressed with the carb!
A Holley 4bbl carb on a 1bbl center mount DP intake... 4-into-1! How do you keep the fuel atomized in the intake without heat riser tubes?
If I do my math correctly, a 450cfm 4bbl Holley carb (smallest of the 4bbl Holley carbs) can flow enough (CFM) to get a 122ci (2000cc) engine up to 15,000rpm! Or a 98ci (1600cc) engine up to 19,000rpm!
That might be a bit too much carb for your engine... but it sure does look cool! |
X2, what are the specs on that engine? |
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Gulfaholic Samba Member
Joined: January 18, 2017 Posts: 14
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Posted: Thu May 25, 2017 9:00 am Post subject: Re: Burnt distributor on msd ignition |
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I found the back side bolt holding the distributor cap down stripped out. This was probably causing the cap to be loose. Might have to replace the distributor itself.
Don't know what spark plugs are in it. I'll pull them out and check. Probably will replace them. What would a good spark plug to run with this set up?
I got the bug exactly the way you see it. I really don't like the 4 bbl carb set up. It does have a hard hesitation around 1/4 throttle. Feels like it's chocking out.
How do I find out what size motor is in it?
Thanks for all the info |
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sjbartnik Samba Member
Joined: September 01, 2011 Posts: 5986 Location: Brooklyn
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Posted: Thu May 25, 2017 1:01 pm Post subject: Re: Burnt distributor on msd ignition |
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Gulfaholic wrote: |
How do I find out what size motor is in it?
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Tear it down and measure the pistons & cylinders.
(or ask the owner who built it/had it built) _________________ 1965 Volkswagen 1500 Variant S
2000 Kawasaki W650 |
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ashman40 Samba Member
Joined: February 16, 2007 Posts: 15975 Location: North Florida, USA
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Posted: Thu May 25, 2017 2:32 pm Post subject: Re: Burnt distributor on msd ignition |
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I'd like to see the adapter that allows a square flange 4bbl carb to mount to the 34mm two screw intake port of the stock DP manifold! _________________ AshMan40
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'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76760 Location: Sneaking up behind you
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Posted: Thu May 25, 2017 2:34 pm Post subject: Re: Burnt distributor on msd ignition |
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ashman40 wrote: |
I'd like to see the adapter that allows a square flange 4bbl carb to mount to the 34mm two screw intake port of the stock DP manifold! |
That's a lot of carbonation. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare |
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[email protected] Samba Member
Joined: May 17, 2003 Posts: 4863 Location: Harmony, PA
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Posted: Thu May 25, 2017 6:55 pm Post subject: Re: Burnt distributor on msd ignition |
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Gulfaholic wrote: |
Don't know what spark plugs are in it. I'll pull them out and check. Probably will replace them. What would a good spark plug to run with this set up? |
Most I know with a MSD setup run one heat range colder than a factory plug. I've been running more NGK plugs than Bosch lately. Everything I've read on NGK plugs has their heat range of 5 being equal to a stock Bosch 8, so I would start with a 6 NGK. Depending on your heads designates which plug you need.
NGK 7331 BP6HS would be for a 14mm 1/2 reach
NGK 7333 BP6ES would be for a 14mm 3/4 reach
NGK 1068 DP6EA-9 would be for a 12mm 3/4 reach
As for the gap, I know some that run .055 with an MSD distributor, but I would stay along the lines of .035-.040. |
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mark tucker Samba Member
Joined: April 08, 2009 Posts: 23937 Location: SHALIMAR ,FLORIDA
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Posted: Thu May 25, 2017 7:10 pm Post subject: Re: Burnt distributor on msd ignition |
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do you see where it says PROCOMP????? thats a pos procomp dist not MSD. there is your issue. I have 2 new procomp dist hear at my place and there both Peices of shit!! both are diferent from each other, both have different issues and different parts. there china shit by way of austrailia. they sold new for less than $30!!!!! how can that be you ask??? because there peices of shit. and now days they have changed ther name again to speedmasters and will probably be another name this time next year. they were big at swap meats( the big multie acre specialized originized swap meats. they sell almost everything from aluminum heads , roller rockers to dist to fuel injection and everything inbetween all china shit. last big time swap meat I was at many venders had sines on their booths stating "we do not will not, sell any procomp or speed master shit!! so dont ask" oh somany venders with the same sines. at 1 time thier shit was ok, but the kid took over and sublet everything to china and cut out his home country(Australia), it's shit. buy a cb magna spark kit and install it throw that stuff away unless you have the means to totaly rebuild remachine what you have....so it works right. |
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76760 Location: Sneaking up behind you
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Posted: Thu May 25, 2017 7:23 pm Post subject: Re: Burnt distributor on msd ignition |
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mark tucker wrote: |
do you see where it says PROCOMP????? |
Could just be a Procomp cap. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare |
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Bashr52 Samba Member
Joined: July 16, 2006 Posts: 5666 Location: On an island in VA
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Posted: Fri May 26, 2017 5:51 am Post subject: Re: Burnt distributor on msd ignition |
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ashman40 wrote: |
I'd like to see the adapter that allows a square flange 4bbl carb to mount to the 34mm two screw intake port of the stock DP manifold! |
It could be a "johnny 4-play" setup, but the bolt pattern looks to small. MY guess is some kind of adapter on a progressive center section? |
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ashman40 Samba Member
Joined: February 16, 2007 Posts: 15975 Location: North Florida, USA
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Posted: Fri May 26, 2017 7:55 am Post subject: Re: Burnt distributor on msd ignition |
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Gulfaholic wrote: |
I found the back side bolt holding the distributor cap down stripped out. This was probably causing the cap to be loose. Might have to replace the distributor itself. |
That could very well be the culprit.
That distributor appears to be a high quality unit than the Chinese clones of 009s. If you can repair it, it could save you a bit of $$. A stripped screw can usually be repaired. Helicoil, inserts, even epoxy steel (JB Weld) could be used as a last resort. That coil is a high output unit but may not work with a different distributor or ignition system. So replacing the distributor with a less expensive one could result in replacing then entire ignition system.
Gulfaholic wrote: |
Don't know what spark plugs are in it. I'll pull them out and check. Probably will replace them. What would a good spark plug to run with this set up? |
My question was not about changing the make of spark plugs but rather a check in to the condition and gap of the plugs. The advantage of a HO ignition system is a more reliable/hotter spark to ignite the mixture. You get this from higher voltages (~60Kv) and the higher voltages allow a larger spark plug gap which means a larger/longer spark.
I personally like NGK copper core spark plugs. I'm not into any fancy electrodes made from exotic materials like platinum or iridium... or exotic shapes like U-shaped or forked.
I can't suggest a spark plug model# because your heads may not be stock (based on the carb and distributor). See gkeeton's list above of NGK spark plugs for different size spark plug holes. You need to confirm which plugs size you have. Not just diameter of the threaded area but also by length.
Gulfaholic wrote: |
I got the bug exactly the way you see it. I really don't like the 4 bbl carb set up. It does have a hard hesitation around 1/4 throttle. Feels like it's chocking out. |
I'd think the smaller engine cannot produce enough vacuum to maintain a consistent flow of air thru the 2 or 4 carb throats. If the airflow down the carb drops below a minimum point the fuel stops flowing (fuel flow is dependent on air flow -- that is how a carb works). When the fuel flow stops it takes extra effort to get it flowing again. A larger engine would maintain a minimum flow of air-fuel thru the carb.
The other thing is the accelerator pump. The volume of fuel being squirted could be too large for the small engine. Holley carbs used different sized cams and jets to control the volume of fuel squirted. Just like the stock Solex carbs, you want fuel squirting from the accelerator pump nozzles as soon as the throttle arm moves, no delay.
Gulfaholic wrote: |
How do I find out what size motor is in it? |
Unfortunately, unless the PO told you the size of the engine or the bore and stroke of each cylinder you cannot really tell without removing a head and measuring the bore x stroke. While you may be able to judge the stroke thru the spark plug hole (never actually tried), there is usually nothing on the outside to give you a clue on the diameter of a cylinder.
Displacement is calculated:
Volume = pi x radius^2 x height x f-cylinders
For a stock 1600cc (actually 1585cc) engine with 85.5mm diameter pistons and 69mm stroke crankshaft....
Volume = 3.1415 x (8.55cm/2)^2 x 6.9cm x 4 = 1585cc _________________ AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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